An electrified vehicle includes a traction battery. In a plug-in type of electrified vehicle, the traction battery may be coupled to charging equipment to charge the traction battery. The traction battery is normally configured to operate within a predetermined state of charge range. The upper limit of the predetermined state of charge range is normally at or below a rated charge capacity of the traction battery (e.g., less than 100% state of charge). However, there may be conditions in which a traction battery (or a subset of cells of the traction battery) is charged above the rated charge capacity. For example, current measurement errors may cause the state of charge to be underestimated. If the traction battery is overcharged for a certain period of time, the temperature of the traction battery may increase above a temperature limit. The over-temperature condition is further characterized by a rapid increase in temperature. A battery management system may be configured to monitor the thermal state of the traction battery to detect over-temperature conditions. Typical battery management systems monitor temperature sensors associated with the traction battery to detect a temperature of the traction battery that is above a predetermined temperature.